Process of making anthraquinone dyes.



UNTTEn STATES Patented March 15, 1904.

PATENT OFFICE.

EDUARD HEPP, OF FRANKFORT-ON-THE-MAIN, AND ERNST WOLPERT, OF HOCHST-ON-THE-MAIN, GERMANY, ASSIGNORS TO FARBWERKE, VORM. MEISTER, LUCIUS & BRUNING, OF HOCHST-ON-THE-MAIN, GERMANY,

CORPORATION OF GERMANY.

PROCESS OF MAKING ANTHRAQUINONE DYES.

SPECIFICATION forming part of Letters Patent No. 754,768, dated March 15, 1904.

Application filed October 15, 1903. Serial No. 177,176. (No specimens.)

T at whom it may concern.-

Be it known that we, EDUARD HEPP, Ph. D. residing at Frankfort-on-the-Main, and ERNST WOLPERT, Ph. D., residing at H6chst-on-the- Main, Germany, both citizens of the Empire of Germany, have invented certain new and useful Improvements in the Process of Making new Anthraquinone Dyestuffs, of which the following is a specification.

It is known by Letters Patent No. 7 34,325 that by heating 1:415:53 leucotetraoxyanthraquinone with primary aromatic amins in presence of salts thereof dialphylidodioxyanthraquinones are obtained, which in their sulfonated form dye chrome mordanted or unmorclan-ted wool fast green shades.

Our new process consists in the production of very valuable blue coloring-matters from said leucotetraoxyanthraquinone by condensing it with the sulfo-acids of primary aromatic [OHszNHzzsOsH I 1 :4:6,] para amidobenzylsulfo-acid and so on)in the form of their salts or together with suitable acetates, such as the acetates of alkalies. The sulfo-acids are thus heated with the leucotetraoxyanthraquinone in presence of a condensing agent, such as boric acid, and of a suitable solvenF-such as water, acetic acid, glycerin, acetin, and so on and after the condensation having taken place the melts are diluted with water and the dyestuffs are precipitated from their aqueous solutions with common salt or in another suitable manner. The dyestulfs thus obtained are when dry dark-blue powders, soluble in water and ammonia with a blue color. They dye chrome mordanted and unmordanted wool Very fast blue shades.

The following example will serve to further illustrate the manner in which our invention can be carried out. The parts are by weight: Ten parts of 1:4:5z8 leucotetraoxyanthraquinone are mixed with ten parts of crystallized boric acid, thirty parts of sulfanilate of sodium, ten parts of sodium acetate, and seventy parts of dilute acetic acid of fifty-percent. strength, and the mixture is heated for some hours on a water-bath until no further increase in the quantity of the coloring-matter produced is observed. The melt is then poured into water, the aqueous solution is heated to boiling, filtered, and the dyestuff is precipitated with common salt. It is filtered ofi, pressed, and dried.

Instead of 1.4.5.8 leucotetraoxyanth-raquinone the corresponding tetraoxyanthraquinone may be employed in this process, together with a suitable reducing agent, such as stannous chlorid and sodium acetate, the leucotetraoxyanthraquinone reacting then in the nascent state.

When pulverized, our new product is a dark-blue powder which is soluble in water and ammonia with a blue color and is completely separated by adding to the aqueous solution an excess of mineral acids. It is soluble in concentrated sulfuric ,acid, yielding a blue solution. By heating with dilute caustic alkalies and zinc-dustit gives an orange solution, which when filtered assumes the initial blue color on exposure to the air. It dyes chrome mordanted and unmordanted wool blue shades distinguished by their fastness to light, acids, and alkalies.

Having now described our invention and the manner of performing same, what we claim 1. The herein-described process of making new anthraquinone dyestuifs, which consists in treating 1.4. 5.8 leucotetraoxyanthraquinone with the sulfo-acids of primary aromatic amine and then isolating the resulting dyestufl sulfonic acids from the mixture of reaction in the manner hereinbefore described, substantially as set forth.

2. The herein-described process of making a new anthraquinone dyestulf, which consists in treating 1.4.5.8 leucotetraoxyanthraquinone with sulfanilic acid and then isolating the resulting dyestufi? sulfonic acid from the mixture of reaction in the manner hereinbefore described, substantially as set forth.

3. The herein-described new dyestufi' sulfonic acids, obtainable by condensing 1.4.5.8 leucotetraoxyanthraquinone with the srlli'oacids of primary aromatic amins, which dyestuffs, when dry and pulverized, are dark powders, soluble in water and ammonia with a blue color, dyeing Inordanted or unmordanted wool fast blue shades.

4:. The herein-described dyestufl' sulfonic acid obtainable by condensing 1.4E.5.8 leucotetraoxyanthraquinone with sulfanilic acid, being when dry and pulverized a dark-blue powder soluble in water and ammonia with a blue color and which is separated by adding 

